Cubic graphs induced by bridge trisections

Fuente: arXiv
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Main Authors: Meier, Jeffrey, Thompson, Abigail, Zupan, Alexander
Format: Preprint
Published: 2020
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_version_ 1866912034161950720
author Meier, Jeffrey
Thompson, Abigail
Zupan, Alexander
author_facet Meier, Jeffrey
Thompson, Abigail
Zupan, Alexander
contents Every embedded surface $\mathcal{K}$ in the 4-sphere admits a bridge trisection, a decomposition of $(S^4,\mathcal{K})$ into three simple pieces. In this case, the surface $\mathcal{K}$ is determined by an embedded 1-complex, called the $\textit{1-skeleton}$ of the bridge trisection. As an abstract graph, the 1-skeleton is a cubic graph $Γ$ that inherits a natural Tait coloring, a 3-coloring of the edge set of $Γ$ such that each vertex is incident to edges of all three colors. In this paper, we reverse this association: We prove that every Tait-colored cubic graph is isomorphic to the 1-skeleton of a bridge trisection corresponding to an unknotted surface. When the surface is nonorientable, we show that such an embedding exists for every possible normal Euler number. As a corollary, every tri-plane diagram for a knotted surface can be converted to a tri-plane diagram for an unknotted surface via crossing changes and interior Reidemeister moves.
format Preprint
id arxiv_https___arxiv_org_abs_2007_07280
institution arXiv
publishDate 2020
record_format arxiv
spellingShingle Cubic graphs induced by bridge trisections
Meier, Jeffrey
Thompson, Abigail
Zupan, Alexander
Geometric Topology
Combinatorics
57Q45, 57M50, 05C15
Every embedded surface $\mathcal{K}$ in the 4-sphere admits a bridge trisection, a decomposition of $(S^4,\mathcal{K})$ into three simple pieces. In this case, the surface $\mathcal{K}$ is determined by an embedded 1-complex, called the $\textit{1-skeleton}$ of the bridge trisection. As an abstract graph, the 1-skeleton is a cubic graph $Γ$ that inherits a natural Tait coloring, a 3-coloring of the edge set of $Γ$ such that each vertex is incident to edges of all three colors. In this paper, we reverse this association: We prove that every Tait-colored cubic graph is isomorphic to the 1-skeleton of a bridge trisection corresponding to an unknotted surface. When the surface is nonorientable, we show that such an embedding exists for every possible normal Euler number. As a corollary, every tri-plane diagram for a knotted surface can be converted to a tri-plane diagram for an unknotted surface via crossing changes and interior Reidemeister moves.
title Cubic graphs induced by bridge trisections
topic Geometric Topology
Combinatorics
57Q45, 57M50, 05C15
url https://arxiv.org/abs/2007.07280